// SPDX-FileCopyrightText: 2002-2023 PCSX2 Dev Team
// SPDX-License-Identifier: LGPL-3.0+

#pragma once

#include "common/Pcsx2Defs.h"

#ifdef _WIN32
#include "common/RedtapeWindows.h"
#elif defined(__linux__)
#include <libaio.h>
#elif defined(__POSIX__)
#include <aio.h>
#endif
#include <memory>
#include <string>

class Error;

class AsyncFileReader
{
protected:
	AsyncFileReader()
		: m_dataoffset(0)
		, m_blocksize(0)
	{
	}

	std::string m_filename;

	u32 m_dataoffset;
	u32 m_blocksize;

public:
	virtual ~AsyncFileReader(){};

	virtual bool Open(std::string filename, Error* error) = 0;

	virtual int ReadSync(void* pBuffer, u32 sector, u32 count) = 0;

	virtual void BeginRead(void* pBuffer, u32 sector, u32 count) = 0;
	virtual int FinishRead() = 0;
	virtual void CancelRead() = 0;

	virtual void Close() = 0;

	virtual u32 GetBlockCount() const = 0;

	virtual void SetBlockSize(u32 bytes) {}
	virtual void SetDataOffset(u32 bytes) {}

	const std::string& GetFilename() const { return m_filename; }
	u32 GetBlockSize() const { return m_blocksize; }
};

class FlatFileReader final : public AsyncFileReader
{
	DeclareNoncopyableObject(FlatFileReader);

#ifdef _WIN32
	HANDLE hOverlappedFile;

	OVERLAPPED asyncOperationContext;

	HANDLE hEvent;

	bool asyncInProgress;
#elif defined(__linux__)
	int m_fd; // FIXME don't know if overlap as an equivalent on linux
	io_context_t m_aio_context;
#elif defined(__POSIX__)
	int m_fd; // TODO OSX don't know if overlap as an equivalent on OSX
	struct aiocb m_aiocb;
	bool m_async_read_in_progress;
#endif

	bool shareWrite;

public:
	FlatFileReader(bool shareWrite = false);
	~FlatFileReader() override;

	bool Open(std::string filenae, Error* error) override;

	int ReadSync(void* pBuffer, u32 sector, u32 count) override;

	void BeginRead(void* pBuffer, u32 sector, u32 count) override;
	int FinishRead() override;
	void CancelRead() override;

	void Close() override;

	u32 GetBlockCount() const override;

	void SetBlockSize(u32 bytes) override { m_blocksize = bytes; }
	void SetDataOffset(u32 bytes) override { m_dataoffset = bytes; }
};

class MultipartFileReader final : public AsyncFileReader
{
	DeclareNoncopyableObject(MultipartFileReader);

	static const int MaxParts = 8;

	struct Part
	{
		u32 start;
		u32 end; // exclusive
		bool isReading;
		AsyncFileReader* reader;
	} m_parts[MaxParts];
	u32 m_numparts;

	u32 GetFirstPart(u32 lsn);
	void FindParts();

public:
	MultipartFileReader(AsyncFileReader* firstPart);
	~MultipartFileReader() override;

	bool Open(std::string filename, Error* error) override;

	int ReadSync(void* pBuffer, u32 sector, u32 count) override;

	void BeginRead(void* pBuffer, u32 sector, u32 count) override;
	int FinishRead() override;
	void CancelRead() override;

	void Close() override;

	u32 GetBlockCount() const override;

	void SetBlockSize(u32 bytes) override;

	static AsyncFileReader* DetectMultipart(AsyncFileReader* reader);
};

class BlockdumpFileReader : public AsyncFileReader
{
	DeclareNoncopyableObject(BlockdumpFileReader);

	std::FILE* m_file;

	// total number of blocks in the ISO image (including all parts)
	u32 m_blocks;
	s32 m_blockofs;

	// index table
	std::unique_ptr<u32[]> m_dtable;
	int m_dtablesize;

	int m_lresult;

public:
	BlockdumpFileReader();
	~BlockdumpFileReader() override;

	bool Open(std::string filename, Error* error) override;

	int ReadSync(void* pBuffer, u32 sector, u32 count) override;

	void BeginRead(void* pBuffer, u32 sector, u32 count) override;
	int FinishRead() override;
	void CancelRead() override;

	void Close() override;

	u32 GetBlockCount() const override;

	static bool DetectBlockdump(AsyncFileReader* reader);

	s32 GetBlockOffset() { return m_blockofs; }
};